Is it fine to take beta-blockers daily or should I take only when I get palpitations?

Hello doctor,

I am a 57-year-old female. Here is my question constant heart palpitations and fluttering, continuous feeling of adrenaline rushing along with palpitations very bad at night but also during the day when sitting in doing nothing palpitations often make you feel nauseous on a 1 to 10 scale they are about an eight. All labs are normal ECG, echo, and Holter monitor are all normal. Doctor cannot figure it out and prescribed Propranolol 10 mg, told me to try these once a day. Yesterday after doctor visits heart palpitations for four hours got fed up and took one tablet one hour later, all palpitations and adrenaline rush was gone. Slept for the first time without being woke up having to cough to stop the palpitations. Had angio done approximately two years ago due to suspected heart attack or arrhythmia at home with all classic signs crushing chest pain jaw neck left arm down to the floor nauseated? Even with that lab test came back good the next day. Had carotid artery surgery two years ago to remove a piece of plaque in right carotid artery none found anywhere else no stent needed. Again all labs are good cholesterol not high on statins and warfarin. I must be perplexing to all doctors because they cannot figure it out. Was put on warfarin approximately 15 years ago due to DVTs as a result of a surgery, always therapeutic. So I had a heart attack or arrhythmia a few years back the angio came out the great doctor said everything looked fine now I have these crazy heart palpitations that would not stop. They go away as soon as I take the beta-blocker. I am told that beta-blockers even though anti-arrhythmic can also be pro arithmetic as well should I take this every day or should I only take this when I start to feel palpitations.